Expression of a mannose/fucose membrane lectin on human dendritic cells

Dendritic cells (CD) are the most efficient antigen presenting cells for T lymphocytes. CD1a+ CD14- CD with high antigen-presenting capacities can now be obtained easily from adherent peripheral blood monocytes by culture in the presence of granulocyte/macrophage colony-stimulating factor and interleukin-4 (Sallusto et al., J. Exp. Med. 1994. 179: 1109). Human macrophages express a membrane lectin, or sugar-specific receptor, which specifically mediates the binding and endocytosis of mannose- and fucose-terminated glycoproteins and is involved in the phagocytosis of pathogens. A similar lectin activity was sought on cultured human DC using flow cytometry and confocal microscopy to detect binding and internalization of fluoresceinated neoglycoproteins [bovine serum albumin (BSA) substituted with sugar residues]. Several neoglycoproteins, especially alpha-L-fucosyl-, alpha-D-mannosyl-, N,N'-di-acetyl-beta-chitobiosyl- and beta-D-glucosyl-BSA, were endocytosed by cultured human CD1a+ DC as well as by CD1a- CD14- cells which were also obtained in the culture. Fuc-BSA and Man-BSA had the same number of binding sites (1.7 x 10(6)/cell) on CD1a+ DC, and bound with an affinity constant close to 10(7) 1/mol. Inhibition experiments indicated that these two neoglycoproteins bound to the same membrane lectin. CD1a+ and CD1a- cells were both labeled by an antiserum specific for the human macrophage mannose receptor. The membrane lectin specific for mannose and fucose that is evidenced in these experiments on cultured DC may be similar to the macrophage membrane lectin or may share functional and structural properties with it.     

Deep levels,electrical and optical characteristics in SnTe-Doped GaSb Schottky Diodes

The GaSb layers investigated were grown directly on GaAs substrates by molecular beam epitaxy (MBE) using SnTe source as the n-type dopant. By using admittance spectroscopy, a dominant deep level with the activation energy of 0.23-0.26 eV was observed and its concentration was affected by the Sb₄/Ga flux ratio in the MBE growth. A lowest deep-level concentration together with a highest mobility was obtained for GaSb grown at 550°C under a Sb₄/Ga beam equivalent pressure (BEP) ratio around 7, which should correspond to the lowest ratio to maintain a Sb-stabilized surface reconstruction. In the Hall measurement, an analysis of the temperature-dependent mobility shows that the ionized impurity concentration increases proportionally with the sample’s donor concentration, suggesting that the ionized impurity was introduced by an SnTe source. In addition, optical properties of an undoped p-, a lightly and heavily SnTe-doped GaSb layers were studied by comparing their photoluminescence spectra at 4.5K.     

Consumption of reduced-fat products: effects on parameters of anti-oxidative capacity

Plasma levels of fibrinogen, factor VIIc and prothrombin fragment F1 + 2, a marker of thrombin generation in vivo, were studied in 68 subjects with serum total cholesterol (TC) levels between 135 and 349 mg/dl but without clinical evidence of cardiovascular disease and other atherosclerotic risk factors. F1 + 2 plasma levels were directly correlated with TC (p < 0.0004), low-density lipoprotein cholesterol (LDL-C; p < 0.0018) and factor VIIc (p < 0.024). Thirty-five subjects with TC greater than 249 mg/dl (median value of the whole group) showed higher levels of F1 + 2 (p < 0.0001) and fibrinogen (p < 0.0015) than those with TC lower than 249 mg/dl. In subjects with TC > 249 mg/dl and F1 + 2 > 1.2 nM (median value of the whole group), a cholesterol-lowering drug (simvastatin) was able to reduce F1 + 2 (p < 0.009) as well as TC and LDL-C. This study shows a relationship between serum cholesterol and the rate of thrombin generation supporting the hypothesis that a hypercoagulable state may occur in hypercholesterolemic subjects before the onset of clinical evidence of atherosclerotic cardiovascular disease.     

铝－锂合金中δ’（Al＿3Li）沉淀相时效粗化行为及体积分数的测定

对经固溶处理的二种Ａｌ－Ｌｉ合金（１．９４ｗｔ．％Ｌｉ和２．７５ｗｔ．％Ｌｉ）的时效过程进行了研究。结果表明：δ’的生长速率遵从Ｏｓｔｗａｒｄ粗化动力学。１．９４ｗｔ．％Ｌｉ合金δ’产生于时效过程中，而２．７５ｗｔ．％Ｌｉ合金的δ’产生于时效的前期阶段。前者的表现体积分数明显大于根据相图估算的数伍，真实体积分数则与此值接近；后者的体积分数低于根据相图估算的数值，这可能归咎于δ’固相线的位置、统计学误差及Ｌｉ更易在时效过程中贫化。     

Preparation of Metal-Coated Carbon Fiber Reinforced Composites and Their Electromagnetic Properties

Medium temperature curing by infrared radiation was used to prepare electromagnetic wave absorbing multilayered plastic matrix composite materials containing metal-coated carbon fibers (MCFs). The electromagnetic properties of the materials were investigated by frequency scanning tests with microwave vector network analyzer. It is found that the electromagnetic parameters, mainly permittivity of the composites increase significantly with the addition of MCFs, which gives the composites good designability as thin, light-weight EM wave absorbers. It is also shown that MCFs can improve on the EM wave energy attenuating property of the composites by widening the work frequency band width and raising the absorptive peak     

On Toroidal Azulenoids and Other Shapes of Fullerene Cage

The possibility of toroidal cages of carbon with repeating five and seven membered ring pairs (azulene units) upon their surfaces is briefly discussed. Some of the difficulties in recognising possible fullerene cage shapes are pointed out.     

Topology and Stability of Trivalent Polyhedral Clusters

An algorithm to generate the molecular graphs of the trivalent clusters is presented. All the polyhedral trivalent cages with 4-16 vertices are enumerated, with particular attention being given to their symmetry, spectra and stability. The relative stability of isomers is not decided solely by their symmetry. A new kind of spectral phenomenon is reported. This is the occurrence of graphs having the same HOMO-LUMO gap, the same E and the same even-order moments. We refer to it as 'pseudo-isospectrality'.     

ACT3: a high-speed, high-precision electrical impedance tomograph

Presents the design, implementation, and performance of Rensselaer's third-generation adaptive current tomograph, ACT3. This system uses 32 current sources and 32 phase-sensitive voltmeters to make a 32-electrode system that is capable of applying arbitrary spatial patterns of current. The instrumentation provides 16 b precision on both the current values and the real and reactive voltage readings and can collect the data for a single image in 133 ms. Additionally, the instrument is able to automatically calibrate its voltmeters and current sources and adjust the current source output impedance under computer control. The major system components are discussed in detail and performance results are given. Images obtained using stationary agar targets and a moving pendulum in a phantom as well as in vivo resistivity profiles showing human respiration are shown     

Modified FSS response from two sided and closely coupled arrays

A demonstration is presented of a way in which an affected FSS response can be achieved using a two sided structure of dipole arrays sharing the same dielectric layer. Even with these simple elements the results produced resonances well below the grating lobe region, and consequently the instability of these with oblique angles of incidence (up to 75°) was less than 1%. The key to this work was the high coupling between the arrays that was achieved by a relative displacement